In a down-link of a CDMA system, a UE usually only knows some information of the present user, and adopts an interference suppression algorithm for other users. Because the CDMA is an interference-limited system, in order to improve system capacity, an advanced interference user suppression algorithm is developed, which requires more interference user information, such as the number of code channels occupied by each user. By detecting the number of activated code channels, whether a new user enters may be determined, and the detection may be used in user capture, a soft handover procedure, and multi-user detection.
In a code channel detection technology in the prior art, usually a received signal is de-spread according to all spreading codes in a spreading code set, that is, through a spread-spectrum matched filter, symbol energy output from the same spread-spectrum matched filter is accumulated, and when an accumulated value of a spread-spectrum matched filter is greater than a certain noise threshold, it indicates that a code channel corresponding to the spreading code is activated.
In the code channel detection technology in the prior art, only the accumulated value and the noise threshold are compared to determine whether a code channel is activated, and with the simple noise threshold decision, accuracy of detecting the activated code channel is low when noise estimation is not accurate or an interference user signal is weak.